1G Harness Repair Help

[ItsJustin]

Good afternoon again guys!

I am currently in the process of swapping '90 6-bolt into my '87 Mighty Max, with a somewhat frankensteined 91-94 harness.

You must be logged in to view this image or video.

Motor is mounted and sitting happy, but now I'm in the process of trying to reverse engineer whatever the heck one of the previous owners of this harness did, there are so many splices and just straight up cut wires that I've been slowly labeling and repair or removing depending on if I need them.

You must be logged in to view this image or video.

I've gotten the ECU pinouts from the ECMLink website and the wiring schematics from here that I'm using to work through this.
Can anybody tell me what you would possibly want to splice into your O2 sensor and Knock Sensor pins to the ECU? I of course don't know this platform, but I can't think of any reason you'd want that.

You must be logged in to view this image or video.

You must be logged in to view this image or video.

Harness already has GM MAP sensor and IAT sensor provisions spliced in so I assume the last car was running a SD tune if that makes a difference?
Just trying to get an idea before I commit to completely unlooming the whole thing and starting again

Thanks for your time!
-Justin

 

[Djean1G]

Hello I believe the wire cross with the knock sensor to 02 sensor is a hack so there is power to it low but will make the knock sensor read it like it was the knock sensor posaible hack heard it somewhere years back.. good luck you can do it.